metamorphic
Unakite
Altered Granite (Granitic Metamorphic Rock)
Hardness: 6 to 7 on the Mohs scale. Color: Mottled green, pink, and yellowish-brown. Luster: Vitreous to dull. Crystal structure: Typically massive or granular, composed of interlocking mineral grains. Specific gravity: 2.5 to 3.0.
- Hardness
- 6 to 7 on the Mohs scale
- Color
- Mottled green, pink, and yellowish-brown
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6 to 7 on the Mohs scale. Color: Mottled green, pink, and yellowish-brown. Luster: Vitreous to dull. Crystal structure: Typically massive or granular, composed of interlocking mineral grains. Specific gravity: 2.5 to 3.0.
Formation & geological history
Formed through hydrothermal alteration (epidotization) of normal granite, where plagioclase feldspar is replaced by epidote. Geologically associated with orogenic belts and ancient mountain-building events, often Precambrian in age.
Uses & applications
Used primarily as a decorative stone, carved into cabochons, beads, spheres, and small ornamental objects for lapidary and jewelry use.
Geological facts
Unakite was first discovered in the Unaka Mountains of western North Carolina, from which it derives its name. The green color comes from epidote, while the pink is orthoclase feldspar.
Field identification & locations
Easily identified in the field by its distinct, colorful mosaic of pink feldspar and green epidote. Commonly found in glacial drift derived from granitic terranes, such as the Blue Ridge Mountains in the US.
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